Oviposition Behaviour of Cleruchoides noackae (Hymenoptera: Mymaridae) in the Laboratory

Abstract

Thaumastocoris peregrinus has become a major pest in eucalyptus. The most promising control method is the use of the parasitoid, Cleruchoides noackae, but little is known about its biology. Thus, the aim of this study was to investigate the oviposition behaviour of C. noackae in T. peregrinus eggs laid on strips of paper towel in the laboratory. 12 copulated females were placed in a plastic petri dish containing five T. peregrinus eggs and their behaviour was observed for 30 min/female. Several behavioural events were performed: searching for the host, host evaluation, insertion of the ovipositor, internal recognition and oviposition. Time elapsed between the insertion of the ovipositor and its removal varied from two to ten minutes. Learning more about C. noackae biology is very important to understand the dynamics between the parasitoid and its host, aiming at its biological control.

Oviposition behaviour of mated or unmated Cleruchoides noackae (Hymenoptera: Mymaridae)

“…noackae immediately after contact with T . peregrinus eggs agrees with a previous report on this parasitoid, with ovipositor insertion time of 2 to 10 minutes at 22 °C for mated females [ 51 ]. Temperature and humidity may have affected time taken for C .…”

“…The oviposition of C. noackae immediately after contact with T. peregrinus eggs agrees with a previous report on this parasitoid, with ovipositor insertion time of 2 to 10 minutes at 22˚C for mated females [51]. Temperature and humidity may have affected time taken for C. noackae to penetrate T. peregrinus egg chorion and oviposit, since these factors affect host conditions and may modify female parasitoid behaviour [33,54], as reported for Anaphes nitens Girault and Anaphes inexpectatus Huber & Prinsloo (Hymenoptera: Mymaridae) on eggs of Gonipterus platensis Marelli (Coleoptera: Curculionidae), another invasive pest of eucalypts.…”

“…Failure to detect a statistical difference between mated and virgin C. noackae females in oviposition behavior may be due to a limited number of replicates, as the standard errors were relatively large in some instances. However, our number of replicates (n = 10) was similar to PLOS ONE other published articles, including others that studied C. noackae, such as Mutitu et al [24], with n = 10, and Haas et al [51], with n = 12.…”

“…External manipulation of egg by unmated or mated C. noackae females, a process known as evaluation [26], allows recognition of characteristics such as form, texture or movement of the host to verify its suitability for oviposition or to identify non-volatile chemicals released by other females during previous oviposition, thus avoiding superparasitism [47,50]. The time spent by unmated and mated C. noackae probing T. peregrinus eggs with their antennae before inserting the ovipositor was similar to that reported for C. noackae females evaluated in a plastic petri dish for 30 min taking 35 seconds for this behaviour at 22˚C [51]. However, the external evaluation time taken for a female to…”

“…peregrinus eggs with their antennae before inserting the ovipositor was similar to that reported for C . noackae females evaluated in a plastic petri dish for 30 min taking 35 seconds for this behaviour at 22 °C [ 51 ]. However, the external evaluation time taken for a female to recognize and parasitize a host may decrease with successive egg handling experience [ 52 ] and host age due to internal physical and chemical changes in the eggs [ 26 , 53 ], and with the recognition of host chemicals or lesions produced during ovipositor insertion [ 47 ].…”